xby-running-formulas

Every serious runner eventually hits the same wall: computing VDOT, picking pace targets, projecting race times, carving out heart-rate zones, and flipping between min/km and min/mile. These calculations live scattered across half a dozen web calculators, and the two most cited formula systems—Daniels and McMillan—often disagree, leaving the runner to decide which number to trust.
xby-running-formulas folds Daniels, Riegel, and McMillan into a single conversation. Hand it one distance and one finish time, and it returns VDOT, the full five-pace training split (Easy / Marathon / Threshold / Interval / Repetition), race-time projections through Daniels' equivalent-performance method and Riegel's power-law formula, McMillan velocity markers (vLT, CV, vVO2), age- and resting-HR-based training zones via both HRMAX and HRRESERVE approaches, and freeform conversions among min/km, min/mile, km/h, and mph—all formatted and ready to paste into a training log.
It is built for the amateur runner who trains hard but would rather not spend the evening as a human calculator, for the competitor who needs a fast pre-race pacing strategy, and for the coach who likes to cross-check two formula systems before publishing a plan. The core idea is simple: ask once, get a formatted answer, and get back to running.